JPH0567372B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a table that uses a linear motor as a drive unit and is capable of fine movement and rapid movement. (Prior Art) In Japanese Patent Application No. 58-198803, the present inventor has already disclosed that a movable table is movably supported via a linear bearing on a track provided on a fixed bed, and a movable table is rotatably supported on the fixed bed. A ball screw shaft is pivotally supported so as to be movable in the direction and fixed in the axial direction, and a ball nut is screwed onto the ball screw shaft through a steel ball so as to be movable in the rotational direction and the axial direction, and the ball nut is attached to the movable table. A ball spline shaft is rotatably supported on the fixed bed in the vicinity of the ball screw shaft, and an outer cylinder is movable in the axial direction on the ball spline shaft and can rotate together with the ball spline shaft. The outer cylinder is interlocked with the ball nut via an interlocking mechanism, and two rotary motors are drivingly connected to the ball screw shaft and the ball spline shaft, respectively. We have proposed a system in which the feed of the moving table can be changed and controlled in stages from minute feed to rapid feed by appropriately selecting the rotation direction of the rotary motor. (Problems to be Solved by the Invention) However, in the invention of the above-mentioned prior application, since a ball screw and a ball spline are used, the screw shaft or spline shaft may be twisted due to rotational torque, or the space between the screw shaft and the nut or the spline may be twisted. It is inevitable that some backlash occurs between the shaft and the outer cylinder, and as a result, the responsiveness of the moving table is poor, making it difficult to significantly improve positioning accuracy. Furthermore, since the ball screw and ball spline are attached to the movable table, there is a problem in that the weight of the movable table increases and the inertia force becomes large, which deteriorates responsiveness during starting and stopping. Furthermore, there is a problem in that mounting space for the rotary motor, ball screw, and ball spline is required, resulting in an increase in the overall size of the table. Therefore, the present invention has been made by focusing on the above-mentioned conventional problems, and its purpose is to eliminate the need for ball screws and ball splines.
We aim to reduce the weight of moving parts such as the table body, improve responsiveness during starting and stopping, and thereby significantly improve the positioning accuracy of the table body.
Moreover, it is an object of the present invention to provide a compact table with a linear motor that has high rigidity, is resistant to uneven loads and impacts acting on the table body on the left and right sides, and is capable of fine movement and rapid movement. (Means for Solving the Problems) In order to achieve the above object, the table with a linear motor capable of fine movement and rapid movement of the present invention is provided with a recess extending over the entire length in the longitudinal direction on the top surface of the first base. , a first linear bearing is fixed to opposing walls of the recess extending parallel to each other in the recess, a second base is supported relatively movably via the first linear bearing, and the second base is movably supported via the first linear bearing. The base is formed with a rolling element rolling groove in which the rolling elements of the first linear bearing come into contact with each other in a rolling manner, and the upper surface of the second base is provided with a groove that extends over the entire length in the direction of movement of the second base. A second linear bearing is fixed to opposing walls of the recess extending parallel to each other within the recess, and the table body is moved in the same direction of the second base via the second linear bearing. The table body is supported so as to be relatively movable, and the table body is formed with a rolling element rolling groove in which the rolling element of the second linear bearing rolls in contact with the first base, the second base, and the second base. A linear motor is interposed between the base and the table body, a first stator is disposed along the longitudinal direction on the bottom surface of the second base, and a first stator is disposed on the top surface of the first base. A first movable element corresponding to the first stator is disposed, a second stator is disposed along the longitudinal direction on the upper surface of the second base, and the second fixed member is disposed on the lower surface of the table main body. The present invention is characterized in that a second movable element corresponding to the child is disposed, and the pitch of the magnetic pole teeth of the first stator is made different from the pitch of the magnetic pole teeth of the second stator. (Example) Below, an example of a table with a linear motor capable of fine movement and rapid traverse according to the present invention will be described. A first embodiment of the invention is shown in FIGS. 1-18. In FIGS. 1 to 3 showing the overall configuration of a table with a linear motor according to this embodiment, reference numeral 1 denotes a first base fixed to a fixed object (not shown) such as a bed; A recess 1' is formed on the upper surface of the base 1 and extends over the entire length in the longitudinal direction. Two pairs of left and right linear bearings 2,
2; 2, 2 are fixed, and the second base 3 is supported so as to be movable relative to the first base 1 via the linear bearings 2, 2; 2, 2. Furthermore, a recess 3' is formed on the upper surface of the second base 3 and extends over the entire length in the direction of movement of the second base 3. Inside this recess 3', there are two pairs of left and right parts fixed to opposing walls extending parallel to each other of the recess 3'. linear bearing 5,5;
5, 5, the table main body 4 is supported so as to be movable relative to the second base 3 in the same direction. As shown in FIGS. 4 to 6, the first base 1 has a substantially U-shaped cross section, and is linearly connected to the opposite wall of the recess 1' on the inside of both sides by fasteners 6, 6 such as bolts. Bearings 2, 2 are each fixed. Further, as shown in FIGS. 10 to 12, the second base 3 has a substantially U-shaped cross section with both sides of its upper surface projecting upward, and has a protrusion projecting downward on its lower surface. A portion 7 is formed. The protrusion 7 extends over the entire length of the second base 3, and on both sides of the protrusion 7 are two load ball rolling grooves 8 for guiding the load balls 15 of the linear bearing 2.
8 are formed respectively. This second base 3
The width of the base 1 is the same as that of the base 1. Further, linear bearings 5, 5, . . . , which support the table main body 4, are fixed to the opposing walls of the recess 3' inside both sides of the upper surface of the second base 3 by fasteners 6, 6 such as bolts. As shown in FIGS. 7 to 9, the table main body 4 supported by the second base 3 has two strips on both sides that guide the load balls 15 of the linear bearings 5, 5... Load ball rolling grooves 9, 9 are formed. The second base 3 mentioned above
The width of the protrusion 7 and the width of the table main body 4 are formed to have the same size. As described above, the protrusion 7 of the second base 3 is supported at both ends by the linear bearings 2, 2; 2, 2 attached to the first base 1, and the table main body 4 is Connect both ends to the second base 3
Linear bearings installed in 5,5; 5,5
Each table body 4 is supported at both ends by
The mounting structure of the second base 3 has a highly rigid structure. Each linear bearing 2, 5 is shown in Figures 14 to 16.
As shown in the figure, there are two ball rolling grooves 1 on one side.
0 and 10 are provided and a ball escape hole 1 is provided inside.
Bearing block 12 provided with 1 and 11
and a retainer 13 that holds two rows of loaded balls.
, ball rolling grooves 10, 10 and ball escape hole 1
1, 11, and a pair of side covers 14, 14 communicating with the load balls 15, 15...
It is designed to circulate between 11 and 11. The contact angle α between the ball rolling grooves 10, 10 and the loaded balls 15, 15, . Further, as shown in Fig. 2, the gap between the linear bearings 2, 2... between the first base 1 and the second base 3 and both sides of the protrusion 7 of the second base 3 is preloaded. The adjustment is performed using gap adjustment bolts 16, 16, . . . as adjustment means. In other words, clearance adjustment bolt 1
6, 16..., the linear bearing 2 presses the side surface of the protrusion 7 of the second base 3, and the reaction force of the pressing force of the gap adjustment bolts 16, 16... is applied to the second base 3. It acts on the linear bearings 2 on the opposite side via the base 3 and presses them toward the protrusion 7 of the second base 3, thereby applying preload to the load balls 15, 15, . . . Furthermore, linear bearing 5,
5... and the table main body 4 are also adjusted by gap adjustment bolts 16, 16, . . . as preload adjustment means, and a preload is applied to the load balls. On the other hand, first and second linear motors 20 and 21 are interposed between the first base 1 and the second base 3 and between the second base 3 and the table main body 4, respectively. There is. Each linear motor 20, 21 is a linear pulse motor in this embodiment, and the stator 22
and a mover 23,
It operates by inputting pulses to the movable element 23 from a pulse generation source (not shown). First, the configuration of the first linear motor 20 will be explained with reference to FIGS. 17a and 17b.
On the lower surface of the second base 3, a flat stator 22 made of a magnetic material is disposed in the longitudinal direction, while on the upper surface of the first base 1, facing the stator 22, A movable element 23 is attached. Each mover 2
3 has a permanent magnet 24 interposed in the center, and two magnetic cores 25 and 26 are arranged facing each other on the left and right sides thereof, and one magnetic core 25 has a permanent magnet 24 interposed therebetween.
A first magnetic pole 27 and a second magnetic pole 28 which are magnetized to the north pole are formed by the permanent magnet 24, and a third magnetic pole 29 and a fourth magnetic pole 30 which are magnetized to the south pole by the permanent magnet 24 are formed in the other magnetic core 26. is formed. As shown in FIG. 17a, the stator 22 has fixed teeth 22a having a U-shaped cross section extending in a direction substantially perpendicular to the longitudinal direction, and are provided at equal intervals at the same pitch _P1 over substantially the entire length in the longitudinal direction. It is being Each magnetic pole 2
Magnetic pole teeth 27a to 30a having the same pitch as that of the stator 22 are also formed on the magnetic poles 7 to 30, respectively. First magnetic pole 27 and second magnetic pole 28 on the N pole side
includes a first coil 31 and a second coil 32.
are wound and connected in series so that magnetic flux is generated in opposite directions when current flows.
It is electrically connected to a pulse generation source (not shown). On the other hand, a third coil 33 and a fourth coil 34 connected in series are also wound around the third magnetic pole 29 and fourth magnetic pole 30 on the S-pole side, and a pulse generation source (not shown) )It is connected to the. Here, for convenience of explanation, for example, the first magnetic pole 2
The phase of the magnetic pole tooth 28a of the second magnetic pole 28 is shifted by 1/2 pitch (1/2P ₁ ) with respect to the magnetic pole tooth 27a of the third magnetic pole 29. It is assumed that the magnetic pole teeth 30a of the magnetic pole 30 are also shifted in phase by 1/2 pitch (1/2P ₁ ),
Furthermore, the magnetic pole teeth 29 of the third magnetic pole 29 and the fourth magnetic pole 30 on the S-pole side are
It is assumed that a and 30a are out of phase by 1/4 pitch (1/4P ₁ ). First, the operating principle of the linear pulse motor of this embodiment will be explained. 18a to 18d show schematic diagrams illustrating the operating principle of a linear pulse motor, in which a first coil 31 and a second coil 32 are connected to a terminal a, a third coil 33 and a fourth coil 34
A pulse is input from terminal b to the terminal b. In FIG. 18a, the first magnetic pole 27 is connected to terminal a.
(mode) in the direction of exciting the fourth magnetic pole 30 at terminal b in FIG.
FIG. 18d shows a state in which a pulse is input to the terminal b in the direction to excite the third magnetic pole 29 (mode), and in the direction to excite the third magnetic pole 29 to the terminal b (mode). Here, Table 1 shows the magnetic force generation state of each magnetic pole in each mode.

【table】

[Table] As shown in Table 1, in the mode, the magnetic force of the first magnetic pole 27 on the N pole side is strong, and the first magnetic pole 27
The movable element 23 is held in a stable state by the suction force between the movable element 7 and the fixed teeth 22a of the stator 22. On the other hand, the third and fourth magnetic poles 29 and 30 on the S-pole side are each shifted in phase by 1/4 pitch with respect to the fixed teeth 22a of the stator 22. In the mode, the magnetic force by the coil 31 of the first magnetic pole 27 disappears, and the magnetic force of the fourth magnetic pole 30 on the S pole side becomes strong, and the movable element 23 It moves relatively in the direction in which the phase matches that of 22a, and advances by 1/4 pitch (1/4P ₁ ).
At this time, the first and second magnetic poles 27, 2 on the N pole side
8 is out of phase by 1/4 pitch (1/4P ₁ ). Furthermore, in the mode, the magnetic force of the second magnetic pole 28 on the N pole side becomes strong, and the second magnetic pole 28
The movable element 2 is moved in a direction that matches the fixed tooth 22a in phase.
3 moves relatively and advances by 1/4 pitch (1/4P ₁ ),
The third and fourth magnetic poles 29 and 30 on the S pole side are 1/4
The phase is shifted by a pitch (1/4P ₁ ). In the mode, the magnetic force of the third magnetic pole 29 on the S-pole side is strong, and the mover 23 moves relatively in the direction where the third magnetic pole 29 matches the fixed tooth 22a of the stator 22 in phase, and the movable element 23 moves 1/4 pitch. (1/4P ₁ ) Go forward. Further, the mode returns again, and the magnetic force of the first magnetic pole 27 on the north pole side becomes strong, and the movable element 23 moves relatively by 1/4 pitch (1/4P ₁ ) to reach the state shown in FIG. 18a. In this way, by repeating the mode, the pitch is moved by 1/4 pitch (1/4P ₁ ) per pulse. On the other hand, the second linear motor 21 disposed between the second base 3 and the table main body 4 is also connected to the second base as shown in FIGS. 1 to 3 and 7 to 12. It consists of a stator 40 arranged longitudinally on the upper surface side of the table 3 and a movable element 41 arranged on the lower surface side of the table main body 4. A first magnetic pole 42 and a second magnetic pole 43 on the N-pole side, magnetized by the magnet 41a, and a third magnetic pole 44 and a fourth magnetic pole 45 on the S-pole side are formed, and each magnetic pole has a 1st
A coil 46, a second coil 47, a third coil 48, and a fourth coil 49 are wound. Furthermore, this first coil 46, second coil 47,
The third coil 48 and the fourth coil 49 are electrically connected to a pulse generation source (not shown), and the table body 4 is moved relative to the second base 3 by the pulses from the pulse generation source. It is designed to be driven in the longitudinal direction of the base 1. As shown in FIG. 13, the stators 40 and 22 disposed on the upper and lower surfaces of the second base 3 are connected to the pitch P ₂ of the magnetic pole teeth 40a of the stator 40 and the lower stator 22. The pitch _P1 of the magnetic pole teeth 22a is different from that of the magnetic pole teeth 22a. Also, for convenience of explanation, the second linear motor 2
1, for example, the phase of the magnetic pole teeth of the second magnetic pole 43 is shifted by 1/2 pitch (1/2P ₂ ) with respect to the first magnetic pole 42, and the phase of the fourth magnetic pole 43 is shifted with respect to the third magnetic pole 44. 45 also has a magnetic pole tooth phase of 1/2 pitch (1/2
P ₂ ), and furthermore, the magnetic pole teeth of the third magnetic pole 44 and the fourth magnetic pole 45 on the S-pole side are shifted from the magnetic pole teeth of the first magnetic pole 42 and the second magnetic pole 43 on the N-pole side. It is assumed that the phase is shifted by 1/4 pitch (1/4P ₂ ). Therefore, in this case, the first
Similar to the linear motor 20, the mover 41 has a pitch of 1/4 pitch (1/4P ₂ ) per pulse with respect to the stator 40.
Move by step. Next, the operation of the table with a linear motor of this embodiment will be explained. First, when fast forwarding the table body 4 with respect to the first base 1, the mover 23 of the first linear motor 20 (first base 1 side)
When a pulse is input from a pulse generation source (not shown), the movable element 23 moves 1/4 pitch (1/4
P ₁ ), and therefore the table body 4 together with the second base 3 is moved in the longitudinal direction of the base 1 by 1/4 pitch (1/4P ₁ ) per pulse, while the second linear motor When a pulse of opposite polarity is input from a pulse generation source (not shown) to the movable element 41 on the second base 3 (on the side of the table main body 4), the movable element 41 will be 1/4 pitch (1/4P ₂ ) per pulse to the first linear motor 20
Therefore, the table main body 4 is relatively moved in the same direction as the movement direction by the first linear motor 20 with respect to the second base 3. As a result, the table main body 4 is moved relative to the base 1 by a distance (1/4P ₁ +1/4P ₂ ) per pulse, that is, fast-forwarded. Next, in the case of fine movement feeding, the mover 23 of the first linear motor 20 and the second linear motor 21
When pulses of the same polarity are input to the mover 41 of
The first linear motor 20 moves the table body 4 together with the second base 3 in the longitudinal direction of the base 1 by 1/4 pitch (1/4P ₁ ) per pulse.
The table main body 4 is moved by the linear motor 21 to the second base 3 at 1/4 pitch (1/4P ₂ ) per pulse in the opposite direction to the movement direction by the first linear motor 20.
As a result, the table body 4 is moved by a distance (1/4P ₁ −1/4P ₂ ) relative to the base 1,
In other words, it is fed by slight movement. Note that the transfer speed of the table main body 4 becomes faster when the pulse frequency is increased, and becomes slower when the pulse frequency is lowered. Further, the transfer distance is adjusted by the number of input pulses. Furthermore, even if a load is applied to the table body 4, since preload is applied to the linear bearings 2, 2...; 5, 5..., the table body 4 and the
There is no wobbling between the base 3 and the second base 3 and the first base 1, and the contact angle between the ball rolling groove 10 and the load ball 15 is set to around 45 degrees. Because of this, it is possible to evenly support loads from four directions (up, down, left and right), the gap between the linear motor's mover and stator is kept constant, and the thrust and stopping force are always kept constant. Ru. Also, linear bearings 2, 2, which are rolling bearings;
Since it uses 5, 5..., there is less wear, so
Even when a load is applied to the table body 4, there is no fear that the movable element and the stator will interfere with each other, and therefore a large thrust force and stopping force can be obtained by narrowing the gap between the movable element and the stator. Furthermore, since both ends of the table body 4 are supported by linear bearings 2, 2, . Even in such a case, the device attached to the upper surface of the table main body 4 can be stably transferred. In addition, since the linear bearings 2, 2...; 5, 5... were attached to the second base 3 and the first base 1 side, the table main body 4 and the second base 3 to be transferred are attached to the linear bearings 2, 2...;
...; 5, 5... Since the weight is reduced and the inertia is reduced, the responsiveness of starting and stopping is fast. Note that in the linear pulse motor of this embodiment, the fixed teeth are moved by 1/4 pitch per pulse, but any motor that moves by a fixed amount per pulse may be used. Not limited to linear DC motors,
Other types such as a linear synchronous motor may also be used. (Effects of the Invention) The present invention has the above-described configuration and operation, and includes supporting a second base on the first base via the first linear bearing, and supporting the second base on the first base via the first linear bearing. Since the table body is supported via the second linear bearing, the table body and the second base can be moved easily, and by using a linear motor, there is no need to use a ball screw, etc. Weight reduction can be achieved. In particular, since linear bearings are attached to the first and second bases, the weight of the table body and the second base is reduced accordingly, and the moving second base and table The inertial force of the main body is reduced, which improves responsiveness during starting and stopping, and improves positioning accuracy. Furthermore, in the present invention, both ends of the table body are supported by linear bearings on the second base, and the rolling elements of the linear bearings are in rolling contact with the table body itself. A highly rigid support structure with running grooves is adopted, and the second base is also supported at both ends by linear bearings relative to the first base, and the rolling elements of the linear bearing are mounted on the second base itself. A highly rigid support structure similar to that of the table body is provided by forming rolling grooves for rolling elements that come into contact with each other in a rolling manner. In this way, the high-rigidity support structure of the table main body for the second base and the high-rigidity support structure of the second base for the first base are configured independently, and such a high-rigidity support structure Since they are stacked one on top of the other, a highly rigid support structure can be achieved as a whole. Therefore, even if an uneven load is applied to the upper surface of the table body or an impact is applied to the upper surface of the table body, the table body can be stably transported. Furthermore, since there is no torsion of the screw shaft of a ball screw or the like and backlash between the screw shaft and the nut as in the prior art, positioning accuracy is improved. Also, the pitch of the magnetic pole teeth of the stator of the linear motor disposed between the first base and the second base, and the magnetic pole of the stator of the linear motor disposed between the second base and the table body. Since the pitch of the teeth is different, by setting the pitch difference to an appropriate size, the amount of movement of the second base with respect to the first base and the amount of movement of the table body with respect to the second base can be adjusted. Due to the difference or sum of the numbers, it is possible to move the table main body very minutely and rapidly relative to the first base, and it is possible to perform highly accurate positioning. Furthermore, since there is no need for space for the rotary motor, screw shaft, spline shaft, etc., not only is a thin, compact and highly versatile transfer table possible, but the number of parts can be reduced, which improves assembly accuracy. Since the structure is simplified, failures can be prevented as much as possible.

[Brief explanation of drawings]

The drawings show an embodiment of a table with a linear motor according to the present invention, and FIGS. 1 to 18 show an embodiment of the present invention. FIG. 1 is a front sectional view thereof, and FIG. 3 is a sectional view taken along the line shown in FIG. 2, FIG. 4 is a plan view of the base, FIG. 5 is a sectional view taken along the line 4 shown in FIG. sectional view, Figure 7 is a bottom view of the table body,
8 is a side view of the table body, FIG. 9 is a sectional view taken along the line of FIG. 7, FIG. 10 is a plan view of the second base, FIG. 11 is a side view of the second base, and FIG. The figures are a sectional view taken along the line XII-XII in FIG. 10, FIG. 13 is a sectional view taken along the line taken in FIG. Figure 16 is Figure 15-
17a is an enlarged side sectional view of the first linear motor, FIG. 17b is a sectional view taken along the line B-B of FIG. 17a, and FIGS. 18a to d illustrate the operating principle of the first linear motor. FIG. Explanation of symbols, 1...first base, 1', 3'...
Recessed portion, 2... Linear bearing, 3... Second base, 4... Table body, 5... Linear bearing, 20, 21... Linear motor, 22... First
Stator, 23...First mover, 40...Second stator, 41...Second mover, _P1 ...Pitch of magnetic pole teeth of first stator, _P2 ...Pitch of second stator Pitch of magnetic pole teeth.

Claims (1)

[Scope of Claims] 1. A recess extending over the entire length in the longitudinal direction is provided on the upper surface of the first base, a first linear bearing is fixed to opposing walls of the recess extending parallel to each other within the recess, and A second base is supported so as to be relatively movable via the first linear bearing, and a rolling element rolling groove is formed in the second base with which the rolling element of the first linear bearing rolls in contact with the second base. On the other hand, a recess is provided on the upper surface of the second base that extends over the entire length in the direction of movement of the second base, and a second linear bearing is provided in the recess on opposing walls that extend in parallel to each other. The table body is supported so as to be relatively movable in the same direction of the second base via the second linear bearing, and the rolling elements of the second linear bearing are in contact with the table body so as to be able to freely roll. A rolling element rolling groove is formed, a linear motor is interposed between the first base and the second base, and between the second base and the table main body, and a linear motor is interposed between the first base and the second base and the second base and the table main body, and a linear motor is interposed between the first base and the second base and the second base and the table body. A first stator is disposed along the longitudinal direction, a first movable element corresponding to the first stator is disposed on the upper surface of the first base, and a first movable element is disposed on the upper surface of the second base. A second stator is disposed along the longitudinal direction, and a second movable element corresponding to the second stator is disposed on the lower surface of the table main body, and the pitch of the magnetic pole teeth of the first stator and the second movable element are disposed on the lower surface of the table main body. A table with a linear motor capable of fine movement and rapid movement, characterized in that the pitches of the magnetic pole teeth of the two stators are made different.